Merge branch 'develop' into features/mpich

* develop: (43 commits)
  Make libxcb compile with gcc 4.9.
  disable parallel install for glib (found races)
  disable cairo-trace, which is incompatible with older libiberty.h.
  Fix LaunchMon on newer gcc versions.
  Simplify output redirection in spack.util.executable
  Allow completely empty config files.
  Fix create, diy, edit, and repo commands to use multiple repos.
  Add namespace option to find command.
  Temporary fix: Clang is the default compiler on Mac OS X.
  update compiler config test.
  add sanity check on config write as well as validation on read.
  Add jsonschema validation for config files.
  Make text wrapping off by default in tty, add a kwarg for it.
  add/remove/list working for new config format.
  Add Python 3 aliases to our argparse backport.
  All tests that call concretize() need to be MockPackagesTests.
  Fix bug in tests.
  Rework mirror configuration.
  Rework compiler configuration and simplify config.py logic.
  Remove mock_configs; tests no longer modify spack home directory.
  ...

var/spack/mock_configs/site_spackconfig/compilers.yaml

@@ -1,12 +0,0 @@
-compilers:
-  all:
-    clang@3.3:
-      cc: /path/to/clang
-      cxx: /path/to/clang++
-      f77: None
-      fc: None
-    gcc@4.5.0:
-      cc: /path/to/gcc
-      cxx: /path/to/g++
-      f77: /path/to/gfortran
-      fc: /path/to/gfortran

var/spack/repos/builtin.mock/repo.yaml

@@ -0,0 +1,2 @@
+repo:
+  namespace: builtin.mock

var/spack/repos/builtin/packages/cairo/package.py

@@ -14,6 +14,7 @@ class Cairo(Package):
 
     def install(self, spec, prefix):
         configure("--prefix=%s" % prefix,
+                  "--disable-trace", # can cause problems with libiberty
                   "--enable-tee")
         make()
         make("install")

var/spack/repos/builtin/packages/gdb/package.py

@@ -6,7 +6,7 @@
 # Written by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
 # LLNL-CODE-647188
 #
-# For details, see https://scalability-llnl.github.io/spack
+# For details, see https://llnl.github.io/spack
 # Please also see the LICENSE file for our notice and the LGPL.
 #
 # This program is free software; you can redistribute it and/or modify